Automatic telephone-release.



J. ERICKSON.

AUTOMATIC TELEPHONE RELEASE.

APPLICATION FILED IAN. 22, I907- Patented May 16, 1916.

4 SHEETS-SHEET I A 2%? zvzegmi J. ERICKSON.

AUTOMATIC TELEPHONE RELEASE.

APPLICAHON FILED JAN. 22,

Patented May 16, 1916.

4 SHEETSSHEET 2- lllillllllllwml mmw 7a re @7071 2 6033077 J. ERICKSON.

AUTOMATIC TELEPHONE RELEASE.

Patented May 16, 1916.

4 SHEETSSHEET 3.

Ira/ 72 Z0 2.

Afio rmyef APPLICATION FILED JAN.22| 1907.

ENYYETE OF CHICAGC}. ILLINOIS, ASSIGNOB. BY FEIZ$T TR-UST AND SAVINGS BANK, '1RFL S'IEi3 61- Cl? i FEIQE ES'N ASSIGNMEE TS, TO

EGG. ILLINOIS.

AU'IOMATIC TELEPHONE-375113.; i.

Applicatian filed January 22 190-7,

it known that l, Jena Enicnsox, a nf the United tates of America, and l of Chim g'i, Gaul; cunnty Illinois, lirsenn a vermin new and useful 11nprm'amcnt in Automatic Telephone l'le la; 99s, 01' wliivli inn My invention relatvs tn telephone ex lliang'e stems; in general. but more particu Early to automatic or semi-autmnatic systems. aml espmrially t0 telephone vxvhanga systems in which automatic selectors 01' other trunking switrlias are employed. In systems of this l'liaravler it has been pro pa ed to anlmnalically cut all the line relay liz'idgas of the selvrtnrs or dither switches. sn as in leave unly tinlH'lL'lg't m bridges of the wnnaclm: 0r final connecting switch arr'oss the iaikii'ig; sin-nit luring conversation, and to than mnploy third minlnstors or spevial trunks far raleasing the selectors 0r other similar swim-has. after the two subscribers are l ln'nnqli talking. This. (if wars 2 leaves the talking (i3 'llli; vomparativalv free from bridges a rnss fin} talking (llOllllL (luring vonversatinn liem'aan tiw two subscribers lint at the sania iimv ne 'essitates the use uf trunk lines Mal mmprising three parallel lnnl or special trunk vanllllil'l l being; nawlfor releasing purposes.

The prinripal (lll llf'll of my invention is l-lnrel nra, ilk-e pmwision of an arrangmn'ian' lry wlii l' ll? iivlay ln'iilgz'vs of the Salaam" anil 0th swiivlies---+ex 'ept the Connect of vonzse wmay lie antuniati'vally (at 01 npvnexl up (luring the use 0 any tmnpwi s rily established lalking vii-wit llktWfiTll V Sill riliers, and Nllvlillfi' the autnm livhas In: ring inlays time: tanipm-arily dis COliPPt'iHl from th talking; virrnit may lie l'illlifiifil witi'mat. Eula" use (if tliiiwl minim-tars i alili lira-as. in this Way l nl tain 1 antages whim) arisa frum (aiding: all ing an in} bridges on any established illll at ills same tima I olivi- Uwilcnes thus alerting a saving in wgn wr Specification of Lezters Pate this following a specifica- I sin in) Wajv interfering nl; lines for sivitirliingj mi ns-ss, and only mini leasing purposes when tin iflflflzllllll. The .V nf my invention liilm'lflfltl mar? fully an" 331a Eillfin will a pear In Line a in drawings, Figure 3 a n r mming tlnv vircnits and an pa aas 1 mprisarl 413M. form of m invenlion Figs. 2, 3, l and 5 show lltlifii fora of my in entimi, Figs. ll aml T taken 1' slim in a similar main'isr a sallii alled sul'iscriber (-zinnectad throw, i wntra (Pil'll'l .switvliing apparalizs in r 'tluil ith which I haw (lfi'LiH'l my im'vntion, Elilll in the saiil l av H10 form (if my invention as it up in Fig. i. in Fig; I show the form (3i my invention shown in Fig 1 applied to na fli sillisrrilmns linP, as wall as in aavli trunk line.

figs. h and 7, it will be understoorL ran i-usvnl tlw sauna l-mjnlilion representelil ll" i i l aml 1'. ln ilk} said Figs. 6 and 3 P .lmwn the railing; substation #:maa Im in: alla'ihal to it the Eran-selector l i vpc (lisrlaswi in l nifwl Pal) iimfilslj'llll granted March 13, 1906, :1 iii-rill. l lzia" )n ll will llrivksnn 8% "an that ill? -nlral bailrr .3 has il {a terminal prail'rably g's'mini'lmi al npuratingrvlays: an. narnial in the non-gimznllwl term Batu-11w an Hi? i. by IF-HEH4llH lav (am-tars film sul slrilrar upar'aios l as is; usually tin ens-mm in sys aims in ml lilimi in tln said llwra is shown a swomlselwtm' rannwinr El, ni another selvcf lr I, D for allofitwl to iiie ('iilltl'l linvv inlllltflfll may lilt- We said & l :02: is shown a ringer 100 gvncrawr ii a la: y signaling macliins. 'llia rain-l: Wiaaang darn-a of my invention may 1w i'nnsiilm'ml as an attachn'wnt w (l1 may in vlu ally wanes will: the (antral Ulla-e w: in any Sllllk alilo mannw. in Fig. S a releasing device is used in cm'mwl' i wil earli subsvribirs line, and then:- l also n: {in Mali trunk line between the first-selectors and the secend-selectors; while by the arrangement shown in Fig; 6 it will be seen that my remuch larger than with th arrangement shown in Figs. 6 and 7.

As diagrammatically shown in Fig. 1, my invention comprises two relays 2 and 3 which are doublewound. The windings 4 and 5 of the relay 2 are so arranged that when current is passing through both windings simultaneously the said relay becomes operatn'ely energized and attracts the armature 6, which latter is pivotally mounted at 7. The windings 8 and 9'of the relary 3 are arranged difi'erentiallythat is, when both windings 8 and 9 carry current in the same direction the magnetizing influence of the current in one winding opposes that of the other, hence the relay does not operatively energize. The windings 4 and 8 are connected in multiple; likewise the windin 5 and 9 are also connected in multiple. The operation of the device is as follows: When the spring 10 is pressed onto the ground spring 11 an energizing circuit is established through the relays 2 and 3 asfollows: from the battery?) through the relay 12, switch 13, then the circuit divides, one branch passing through the winding 8 of the relay and the other through the winding 4 of the relay 2, then the branches meet and continue through the springs 10 and 11 to ground. The said relays 2 and 3 both energize and exert an attractive force upon the common armature G, tending to move the said armature toward each relay core; but the relay 3 exerts the greater influence,

since the armature is normally in contact with this relay core, while some little space separates the armature from the core of the relay 2. The attractive force of the relay 3, together with the force due to-the tension of the spring 14, is suflicient to retain the armature 6 in normal position, as shown. Similarly, when the spring 15 is pressed onto the ground spring 11 .an energizing circuit is set up through the windings 5 and 9, with the same result as above stated.

Xow suppose that both springs 10 and 15 are pressed against the ground spring 11 simultaneously.

' cuits are. again established, but since the re- The same energizing cir-.

ture 6 is attracted toward the core of the relay 2, carrying the spring 14 into engagement with the spring 16 and thereby closing a. circuit through the magnet 17. W'hen the springs 15 and 10 return to normal position and break the energizing circuit through the relays 2 and 3, the armature 6, owing to the tension of the spring 14. returns to normal position. The relays 2 and 3 may be wound to any suitable resistance, but with a battery of fifty volts good results are obtained when the windings 4, 5, 8 and- 9 are wound to a resistance of twenty ohms each. I

Inthe modification shown in Fig. 2 the relays 4 and .5 correspond to the windings 4 and 5, respectively, of the relay 2. The relay 3 does not have the windings 9 and 9 differential-1y arranged in this modification. When the spring 10 is pressed onto the ground spring 11 the windings 4 and 8, be-

ing in parallel, as above, carry current, and

the relays 4 and 3energize. The relay 4 attracts its armature 18 and the reiay 3 exerts an attractin" force upon the armature '6; but the letter 15 unable to respond, since it is locked normal'position by the armature 19. /When the. spring 15 is pressed onto the ground'spring 11 the relay 5 and the winding Quarry current, and the relays energize. In this case the armature 19 is attracted, but the armature 6 is still locked in normal position by the armature 18. \Vhen bot-h springs 10 and 15 are pressed simultaneously both relays 4 and 5 attract,

In Fig. 3 is shown an arrangement of relays somewhat like that shown in Fig. 2. In this case, however, when the spring 10 is pressed the relay 4 and relay 3 energize and attract their respective armaturcs 1S and 6, whereby the armature 6 closes the springs 14 and 16 in contact; but the relays 4 and 5 are so arranged that the springs 20 and 21' engage only when both relays operate simultaneously, and the operation of either relay alone is'without effect. The engagement of the springs 15 and 11 produces an energizing circuit through the relay 5 and winding 9 with the above noted result.

Now when the springs 10 and 15 are pressed s multaneously both relays 4 and 5 energize simultaneously; also, the relay 3 operatively energizes, since the windings 8 and 9 are nonditferential. Since all three relays are operatively energized simultaneousiy the circuit through the magnet 17 is closed. When the springs 10, 11 and 15 again disengage, the relays return to their normal positions, as shown.

The device shown in Fig. 4 is essentially diiierent mechanically from the arrangement shown in Fig. l, but the relay Windlugs and circuit connections are exactly the same. The relay is like the relay 2 of Fig. l, and the relay 25 is like the relay 3 of raid Fig. 1 except that each winding and 9 is wound on a separate core. as: shown. The common armature (3 of Fig. l is pivoted at T and secured to the core of the winding 8. 'hcn the spring 10 is grounded the current passes through the windings 4 and in multiple. The attracting influence of the winding h is directed toward the core of the winding l but this core and winding 9 being stationary the attracting force draws the core and winding 8 toward the core or" the winding 9. and this force. together with that of the sprin 14. is sufiicient to overcome the attractive force exerted by the relay 2 on the other end of the armature. and accordingly the armature remains in normal position. Likewise. when the spring 15 is 'ire's ed onto the ground spring ll a similar result is brought about. Evidently. then. the force existing between the two cores oi the windings R and 9 is one of attraction when each winding carries current alone: but when both fil'lllllgh l0 and 15 are grounded simultaneously.both windings and 9 become operative simultaneously. but the force now existing bet-w'een the two cores one of repulsion. since the two wind ings 8 and 9. as explained. are ditierentially arranged. and the armature 6 moves about the pivot point 7. placing the springs 14 and 16 in contact. The ielay 2. of course. becomes energized and a. the relay 3 and thereby renders the operation positive.

In Fig. is shown the modification of Fig. 3, exceptthat the relays i and 5 of Fig. 5 perform other functions in addition to closing an energizing circuit through the magnet 17. When the relay 4 energizes, as explained. the springs and engage, whereby a circuit is closed through the mag net 24. Sin'iilarly. when the relay 5 energizcs. a circuit is closed through the magnet and when both relays 4 and 5 operate si'nultanei'msly a circuit is closed through the magnet 17. The operation of the relays 3. aland 5 in this instance like the opera:

tion of the same relays shown in Fig. 3.

My invention may be used for releasing in an automatic telephone system. and clear uru'lerstaiuling of the operations when used, as a releasing device may he had -from an in connection with explanation of its use the automatic telephone system illustrated in Figs. 6 and 7.

The substation may he of any suitahle or approved type. Sii'ost-ation #5000, for instance, is provided with a receiver 26. transmitter 2T, ringer 28, induction-coil '3 switch-hook 30, impulse wheel 31, cam latch 32 for normally locking the dial. and a dog 33. The impulse wheel 31 is, of course, pro vided with a set of vertical impulse teeth 35 and a rotary impulse tooth an for opera ting, respectively, the vertical impulse spring 38 and the rotary impulse spring 37 with respect to the ground post 3! The substation ground G is permanently connected to the ground spring l0. which latter is normally held away from the ground spring ll by the insulating tip 42 upon the end of the canr latch 32. Said insulating tip normally resisopposite the angled terminal of the ground spring 0, as shown at substation #220 it will be understood, of course. that. the scribers dial (not shown). the impulse wheel 31 and the cam dog 3;; are all rigidly secured to the shaft 43. \Vhile the receiver is on. the switch-hook the switch-hoolccamarm 4i removes the ground spring H from the insulating tip 42. so that the cam-latch 632 falls in front of the pin 45 on the end oi the cam dog 33, whereby it becomes impossible to rotate the dial. When the receiver is removed, however, the switch-hook is raised by a suitable spring (not shown). and the cam-arm 44 by engaging the face 46 of the cam-latch 32 raises the latter sutliciently to permit; the pin 45 to pass under the cum latch when the dial is rotated sutlicicntly. \Vhen the cam-arm 44 leaves its normal position, the ground spring it) falls against the insulating tip 42 and remains there out of engagement with the other ground spring 41 until the dial is rotated. since the cam-' gled section on the end of the ground spring 40. The extremeend of the cam-latch 32, which is engaged by the dog 33, is rounded off in such a manner hat when the dial is rotated the pin 45 slides beneath the said rounded section and raises the cam-latch 32 a trifle, so that the insulating tip 452 may now leave the ground spring 40. permitting the latter to engage the ground spring 41, and thus establishing connection between ground G and the ground post 39. lVhen the receiver is on the hook the cam 47 en gages thv spring 48 and thereby bridges the ringer 28 across the line. lly engaging the spring 48 the said carnarm 47 not only closes the substation ringing circuit, but also separates the springs 51 and 52 and opens the primary circuit; but when the switchiook is up the primary circuit is closed. Furthermore. while the dial is being operated, and. therefore. while the cam 53 of the dog 33 is out of normal position. the primary circuit is opened at the point between the springs 51 and 52. so that no electric impulses which may be deliv red to either of the subscribers line conductors ind.- i shall a 02 circular mnzimi. The rotary relay controls film private magnet \(lliill latter, midvi' cm'tuizs cmiilitimis, cunt-i s tlli vertical and IUllill) mag- M and the relensq lizagliwt 1245, la switch wipers 127. i729 13G, nil which are :shmvn. The said swiicis like the side lswitvli 0f the firstseievstm. has 1: manual 01' first positiun, a secnmi position and a third position. In noriiml position the respective side. switch wipengage the cuntact points 31, 13:2, 133 and 13 i1 SfCiHld pnsifiun thv \"e i1g:1ge .ihe Aact I ms 13. 137 and 138, and in ii pimtiun thecuntzict points 139 1.40,

and l- The min mum divides the cir- Y, If. that passes through ii into two sections l the use 0f the 'g-umlei e s 1:45 and 146.

v Conn-Brim has, in addiimn, ringer i'e- Hi by means of which the. ringer i ii-bridged acres; the tm'mhui i.

in: in signal i/liL culled. ti serum: :1 if ireiztiul windings 155 iii sm'ies with tliv vci iding Play 122. iilintmd l i'r-lii llflfslllg .49 WindiiJ, which windir; whim. i515: ii; third @("Qifilh 11'8 bridged l" A l J on ilre called. A :5 lidsai' bile (IIHlQ 4311-, 14-5 and n s'erivs with the itrai battery, milhzd :mbscriher with when he answers. i. to fllti' lie when .d it in acinss the I subscrm iii 146, and, of the (iiiii in: 5

The windin v :1 linerelay 1 winding, relgiy 154;.

the rotary iixic lb; :1 result Ulhjiiiililri the a G-lun l 1 5,

min

i all} in a iiiiil,

windings 421ml mid which relays upemle as previmisly explained. The SGCOIul-SQSRSUH (i. upon receiving the x'ui'timl and rotary impulses, operates in the usual manner to curry-the slm'lt wipers 109 and il intu engagement with a trunk line leading lu live u anetior-awitch ii. The result of i'elill'titilk; the (liul for the lilzt two digits is (.0 ground the line comiucwi's 3! and 33 again and to energize the C(HHHX vertical and aviary line r-el ziml l The energizin Lire-nit for ths yvi'ticui ine rein) i121 emnpi'ises the winding and of the relvzxeting KiQVlttS A and A and We winding 155 (if the iiilivieiitiail l' f'llly iii-i; and tlme circuit for llio roan-y line ii'ilai ilw winding 5 21ml 9 of will relmsi lg iim'ices and the wimling 15G the illil lifillilll r ch-1; 1M- Th s (ii on film i'elwsing X and A lmfiwn. T relay each im'y um: iinz ys iii 01' of no vi'uwequcnce at IHKUH \0 ill in: izgmh unca'giw ing ten timw lgflfnijr thin vm-liml mag .23 ten times. ni'haxola' iili Mini: v. llilh' 1m .tziri'ieil tn tin i cmmwtm' bank The lie (ii ili ing subscriber is provided with talking current. Since, by the said operationof the relay 157, the battery I) is connected in series with the windings 155 and 156 of the difi'erential relay 154, and through said windings and the windings of the vertical and rotary line relays 1'21 and 122 said battery is bridged across the calling subscribers side of the main line. The calling subscriber is, of course. then provided with talking battery current that flows over the following circuit: from ground Gr to the contact point 142. side switch wiper 130, back-bridge re lay springs 164 and 16-2 to the winding 15(3- of the differential relay 154, rotary line relay 122, through the windings 9 and 5 of the releasing device A, and through the windings 9 and 5 of the releasing device A to the rotary line conductor 63. thence through the transmitter 27 of the substation #5000 to the vertical line conductor 62, through the windings l and 8 of the releasing device A and 4 and 8 of the releasing device A to the vertical line relay 13.1 of the connector thence through the winding 155 springs 55, 5G and 57 into contact. and as a result the windings .3 and 9 of the releasing devices A and A are totally or partially shortcircuited through ground G at the substation and ground G at the connector. As a result the said releasing devices becomeunbalanced, as well as the. differential relay 154 of the connector. As soon as the differential relay 154 of the connector energizes, the energizing circuit for the backbridge relay 157 is then destroyed, which relay upon deenergizing restores the spring 162 to the non-grounded spring 163. As a result the rotary line relay 122. which de energizes at the same time that the relay 54 is unbalanced, reenergizes; and since the vertical linerelay 121 is still energized the line relay release springs 165 and 166 come into contact. energizing the release magnet 126 and producing the release of the connector. The windings 8 and 9 of the releasing devices A and A being neutralized by the current that energizes the line relays 1'21 and 122' of the connectorthe windings 4 and 5 reinforcing each otherthe armature 6 is attracted and the springs 14 and 16 are carried into contact; and in the case of the releasing device A the back-release relay 149 of the selector G is energized, thus energizing the release magnet 99, and in the case of the releasing device A the back-release relay 151 is energized, whereby the release magnet 88 is energized.

Now as soon as the substation release springs'separate, the release circuits are all destroyed and the switches fully restored. Of course. if connection is not established with the desired linefor example, as when the called subscriber isbusy, then when the calling subscriber hangs up his receiver he grounds both the vertical and rotary line conductors simultaneously; but since the connector back-bridge relay isnot energizedthe line relays 121 and 122 energize at the same time over circuits that are already known, and at the same time the releasing devices A and A are unbalanced, as already explained, with, the result that as soon as the substation release springs separate, all the switches are fully restored. The connector, of course. releases at once. I

\Vhen my releasing device is used as shown in Fig. 8 the selector-switch L is somewhat different fromthe selector F and the selector M and the corresponding switch (l (Fig. 6) are also ditferent. the difference between the corresponding switches is 'found in the absence of the release relays, such as the release relay 151 of the selector 'F, and the spring on the private magnet at which one terminal of the release magnet terminates. Said release magnet terminal is instead connected to the spring H of the releasing device A, as shown in said Fig. 8. Otherwise the switches are identical, and like parts being similarly represented, the various parts will be readily recognized upon referring to the drawings. Of course. it will be understood that the operation of the switches when Figs. 8 and 7 are considered together is the same as when Figs. 6 and 7 are considered together, the only diflerence being that when the release occurs the armatures 6 directly energize the release magnets 152 and 153 of the switches M and L, instead of through the medium of a release relay. In the dif ferent drawings different batteries are shown, but the system will operate successfully with only one battery.

From the foregoing it will be seen that I provide automatic means for cutting off or opening up the bridges of the selectors, and that I also provide means for releasing the said selectors without using third conductors in the trunk lines. The relaysin the talking circuit do not interfere with the switching or telephoning operations and are effective in releasing the selectors when the subscribers are through talking. I thus get rid of the bridges on the talking circuit without increasing the amountof copperor In each case other material neeessary for the trunk lines ln'tu'een the sn'itehes. As shown in Fig. l the private wipers ot' the selectors are ineluiied in the energi'/.in; eireuits of the rell'llfll relays ot' the selectors. As shown in Fig. H. however. no release relays are employed tor the seleetors. and the private wipers are not ineluded in any release cirenit the release magnets of the selectors having loeal eireuits \vhieh are closed or eontrolled directly by the speeial relays. the rolls of \\'hieh are in the main line eireuit. As illustrated. however. my invention may be employed in various ways. and may be ehanged or modified more or less \vithout d paiting from the spirit thereot'. For this reason. and for the broader purposes of my invention. l do not limit myself to any par-- tieular form or eonstruetion. So far as l ya am now aware. I am the first to out oil the srlertor bridges. so as to leave only the eon- ;zeetor bridge or bridges aeross the talking "nit during: eonversation. and to then rea e the seleetors without the use of third :wl'rilttlul's in the trunk lines. ore speeiliea ly i'-onsidered. the preferred embodiment at my invention is shown in Fig. 6. shown. the system to \vhieh my invention is applied is operated on the eommon watt i prineiple. eurrent tor ehargzing the lili s Tillers transmitters being derived from su -em l-i atfd at the exehange or ventral t biiously. however. the talking eurreut may be otherwise supplied. in ae- 'rdrinv \iitli any suitable or known praeaitliout departing from the scope or aspeet of my invention. at Ill be seen that the eoils H and i and e lose 13 constitute eleetromagznetie in ans w z' nting a premature release or disumait'i'llflil between subscribers. By this i h at; that the said (oils andeore serve as an elet'tiomagnetie lot-king deviee for pre wining a-"eidental release or diseonneetiou ielore th same is desired.

win. 'ding potential is established for s ribers line. it is clear that means il'al for eleetrieall re i'elling inter-- I uilh a busy subseriber. As guarda tentiuls are provided for the trunks. also true that means are provided for iy trunk.

i 'lmt elaini as my invention is:-

En a. telephone exehange syst m the 'iiuatii-ri of a talking oreuit divided elw'tors t'or eonneeting: said r lay bridge in eaeh of said seiniilged .a-ross the eorresponding:

1. at said ialking eirenit. auxiliary .it means as eeial d with eaeh selector by its relay bridge. mean "i zii wi till wil lryttgnw uein gr use et-nuaon i-alt-rv 1- nism. e nmnin battery means tor suppl iri 'ally repelling interferenre with a euit. and llltllilr ineluding relay rails in the talking eireuit for rel asing said seleetors to normal eolillitiou.

:2. in a telephone exeliange system. the eonibination of a talking eii'fiuit. an automatie s\viteh tor e uneetinej one seetion oi the eireuit \\ith another, a relay bridge in the switch aeross the eorn-sponding section of the talking eireuit. auxiliary electrie means assoeiated with the switeh eontrolled by the relay bridge, means for entting utt' said bridge duringuse of said eirruit for talking. eonunwi battery means for supply ing' talking urreut to said eireuit. and means int-hiding: a relay coil in the talking eireuit for leleasing' and restoring saidautl matie switrh to n rmal eouili'tion.

3. In a telephone exehanpr system. the eombination of a talking eireuit. a plurality of relay bridges aeross the eonduetors of said eirenit. auxiliary #:ireuits ass ciated with earl! bridge and controlled thereby. means for matting all said bridges during use at said rireuif for talking. eommnn bat tery mean. for supplying talking eurrem. t said tll'tllll. and 2i i l in i talking riieuii l'ni retstablishiiig said bridg s on said en y-nit.

l. in a telephone axxwliaiige system. the eonminatioii at a talking! win-nit. a seleetm' tor eoniael'ing one sretion if the eirs-uil with anoth r. a relay bridge. in the selector aeross the eorre piaiding set-lion ot' the tall:- iug: eirruit. aux l' ry elertrie means trolled by vans tor rotting oil or opening iurli -\l in; relay eoils eireuit tor Milking; rel We naeelianism t said seleetor. l lliliifi i. battwy means for earn-at t said eireait. 3' (oils supplying talk ng and lll xilllz-l iarladii one or ova-e I"! in the talking: eireui meehanisni to elease the selwstor.

5. In a telephqzie eyeliangre system. the eombinatiou of an automatie swit h. a line eireuit thereior. release meelianism for said switch, a relay bridge aeross said line rir euit eontrolliug' i nwrlianism. an lomatit' means l'oi utting otl or openingup said bridge dur as. use of the eireni'. l'pr talking. a

for :tiiititillii";

hang.

system. the

[ding liesnbseri't slit-- liming: relay y appar. Mail i for eontroilnl; said means for Sir 'ilyin talkin current. and

ing and called subscribers. relay bridges on said circuit. auxiliilnrv apparatus controlled by each bridge and associated therewith. automatic means for cutting ofl' said bridges during talking. and meansincluding (litter ential relay windings included in said ucuitfor reestablishing'the bridges on said" circuit.

circuit. a trunk'line insaid circuit. a relay bridge on said eircuit. auxiliary apparatus controlled by said bridge and associated therewith. automatic means forcultin r ott or opening up said bridge during talkiiig. and meansincluding a pair of ditl erentiai relay coils included in said trunk line for reestablishing the bridge on the circuit.

9. In a,telephone exchange system, calling and called lines, a trunk line connecting the two. a relay bridge across said trunk line, auxiliary circuits associated with said bridge and controlled thereby. automatic means for cutting ad or opening up said bridge during talking, common battery connections for supplying talking current to the lines, and means including relay coils in the trunkconnection for restoring said bridge to normal condition.

10. In telephone exchange system a talking circuit, a connector and a selector in said circuit, a relay bridge across the con dnctors of said circuit. auxiliary electric apparatus controlled by said bridge, means for cutting ofl' said bridge during talking, means for releasing the connector, common battery connections for supplying talking v currentto the lines. and means including relay coils for releasing the selector and re-- establishing said bridge, each relay coil having both terminals thereof connected with said talking circuit.

11. In .a telephone exchange system, a talking circuit. a bridge across theconductors of said circuit. automatic means for cutting oil or opening, up said bridge during t:-ilking, relay coils in said bridge, operating means having local circuits controlled by said coils. common battery connections for supplying talking current to the lines, and means including relay coils in the talk ing circuit fo recstablishing said first-mentioned relays in bridge on the circuit...

12. In a telephone exchange system, the combination of a talking circuit. selectors having relay bridges across the conductors of said circuit. auxiliary apparatus controlled by each bridge and associated then with. means for cutting off said bridges during use of said circuit for talking, means ml lllCllit l lllg I Qlt tY COllS in the talking circuit for releasingand restoring said selectors to normal ,condition and ,lsltfklllg' mean for ,preyenting a premature release or ill 7 connection between subscribers. 1" telephone ,eschangesystem, the

:eon bi I, pt ;a. talking circuit. an auto- .mat: a \;i,tch, l a\.i;ug a relay bridge across the conductorsnfsaidcircuit. auxiliary appaifatuscont gollcgtlby said bridge and associated. lerewith. means forcuttjng off said fbris'lgaduring. ise.o,t said circuit for talking, means ineludin-garelay coil in the talking circuit tor izeleasing and restoring said automatic snitch. to normal condition. and

electromagnetic electromagnetic;lockingtineans for )re\enting a premature,(releas or disconnection between sabsc giliersg.

1t. Ina telephone exchange system the (-ombinationrpt atalking circuit, a plurality of rel-aydiaidges across the conductors of. said circuit,, a1ia,iliary apparatus controlled l yearh bridge and associated therewith. means.forp,cutting otf said bridges during use of said circuit. for talking, means including relay coils in the talking circuit forreleasing and ,restablishing said bridges on saideiccuitt and electromagnetic locking 7 means :for prerenting. a premature release or .disconnection ;between subscribers.

lfnln {a telephone-exchange system. the combination ota, talkingcircuit, a selector in said circuit,{provided with a relay bridge across theconduetors oflsaid Cll0lllt,Il l1.\'ll iary apparatus-v.controlled by said bridge and associated.therewith, meansifor cutting odor opening np theabridge during use of the circuit. fo wtalking. release -meclianism for said seleetor nieans including one or more relay eoils in the talking Circuit for controlling stlld-illleplli rllism to release the selector. and.electroinagnetie locking means for preventing a premature release or disconnection. betwi n subscribers.

in. In a. telephone exchange system, the comhiuationuif an automatic switch having a line, circuit release mechanism for said switch. a-relay bridge onsaid circuit, aux iliary apparatus controlled by said bridge and associated. therewith. automatic means for cutting oti' or opening up said bridge during, use ot'.-.-the circuit for talking, a relay for controllingsaid mechanism. an energizing circuit forsaid relay including the conductors :ofthe line circuit. said relay having a winding includedv serially in the line circuit, and electromagnetic locking means tor preventing a premature release or disconnection between subscribers.

17. In a telephone exchange system, thbv combination (a gline circuit extending between calling arid called subscribers stations. automatic switches having relay bridges across the conductors of said circuit, auxiliary apparatus controlled bv each bridge and associated therewith. automatic cutting off or opening up said bridge durmeans for cutting of? or opening: up said bridges during nae of the circuit for tallo iug, means including relays for releasing the automatic SWltCllGs, said relays having windings includcd in the line circuit and clcctromagnetic locking mentor for preventing a premature releape or disconnection between subscribers.

18. In a telephone exchange system, the combination of a line circuit bctueen callinn and called subscribers, r lay bridges across the conductors oi said circuit, aux-- i iary apparatus cmit'rolled in each bridge and associated tluu'ewith, autmnatic means for cutting olf said bridges during talking, means including difl'erential rela} windings included in said circuit for releasing and reestablishing the. bridges on said circuit, and electromagnetic locking means for preventing a premature release or disconnection be- Iween subscribers.

it. in a telephone exchange system, a. line circuit, a trunk line in said circuit, a relay bridge on said circuit, auxiliary apparatus controlled by said bridge and associ ted therewith. automatic means for cut- 2: oh or opening) up Said bridge during talking, means including a pair of differential relay coils included in said trunk line 't'or releasing and rci stablishing the bridge on tho circuit, and electromagnetic locking means for preventing a premature release dist aceration between subscribers.

20. In a telephone exchange system callin; and called telephone lines, a trunk line 'connerti m between said telephone lines, a

relay bridge across the conductors of said trunk lino connection, auxiliary apparatus controlled bv said bridge and associated rewith, automatic means for cutting oil or opening up said bridge during! talking, moans inclliullng relay coils: in th trunk conne tion for releasing and restoring said lrid re to normal condition, and electromagnetic locking n -a s for preventing a prouiature relea te or ii connection between sulJ- srribcrs.

721. in a tilupllbl'l i exchange s 'z'stem, a. talking circuit. a connector and a selector in wait] circuit. a relay bridge on the circuit auxiliary apparatus controlled by said bridge and associated thercwith, means; For

' oil or opening up said briogze durq talking. means for releasing; the {ounce tor. Hitflllr including relaycoile to: wleas "ablishiijig said gr. earl; r lay coil having! lt oth icrini- Lberem' 'mineclvil with and Zing we. meal-* dia and i-lmlroniagnotic ll5t'l-ll.. prru-nting a premature rcleioec "r a telepiumc exchange circuit. a bridge was the r and circa amouiai'w lug talking, relay coils in said bridge au;\'- iliary a 'ipai'atus ontrolled lhcrelrv, means including relay coils in the talking circuit for releasing and reestal'ilisl'iing said first- IYiPlltiOliPil relays in bridge on the circuit, and electromagnetic locking means for preventin a. "premature releamc or dinconnec tion between subscribers.

23. In a, telephone exchange no. the combination of a talking circuit. aclcctors each having relay bridges; ucroes the role (llH'llOl'Q f said circuit, means in ldi'il we lei-tor having one motion controlled in one manner and another motion coiltrollr-d in a different manner for connection one sec tion of the talking circuit with another, the said men s in each snitch controlled by its relay bridge. meam for cutting otl' said bridgeu during use of said circuit for talking, means including: relay coils in the talking: circuit for releasing and restoring said selectors to normal condition, a central source of talking current, and means operated from the same source for electrically repelling interference with a busy subscriber.

24. In a telephone exchange :YSHJD. toe combination. of a talking circuit. an auto matic switch having a relay bridge across the conductors of said circuit, means in said switch having one motion controlled in ono manner and another motion controlled in a difl'erent manner for connecting one sec tion of the talking circuit with another, said means controlled lrv said relay bridge.

means for cutting off said bridge during use of said circuit for talking. means including a relay coil. in the talking circuit for releasinn and restoring said automatic ewitrh to normal condition, a central eource, of talking current. and means operated from the same source for electrically repelling in tel-Terence with a busy subscriber.

25. In a. telephone exchange syeltem. the combination of a talking circuit, a plurality of relay bridges across the conductors of said circuit, means associated with each ln'icige. having one motion controlled in ono manner and another motion controlled in a ditl'erentmanner for connectinglgme section of the talking circuit With another and controlled by its relay bridge, means for cutting oil said bridges (luring nae of said circuit for talking. means including relay cons in the talking circuit for reiietablishing bridges on said circuit, a central source talking current. and means operated the same source for electri all v ronu; interference with liner an srriber.

.26. lo a telephone exchange jitfiiiz, the cmnhi l'ion ot' a talking circuit, a selector hating relay bridge acroas the "ondnetorf of said t. inc-nu in selector having one o ,on controlleo one manner 01135111 for said 8010mm. nwuml invilulmgmzr 01* more W121} vmls in HM 'lr-zikmyj m1 *Hw controlling said mosh: mm to {MC-z. Hwy

1:1 mean wan" r during:

MIME imam iinvsa Hm (THIHIHUHWF mid mam :1

the apparatus as wvizih-wi m m "w wining 05' m' vpwflug cumin.

Niki" 51. In an automatic telephone system, a metallic circuit line, a third conductor, a

substation and a selecting switch for said trunk men ns for automatically disconnect-in 1d controlling magnets from said r such selection and connection, renected in the limbs of said trunk ans controiled by said relays for causin said selecting switch to disconnect said line from said trunk line, and a battery circuit which is closed during conversation and which includes the two sides of said trunk line in series.

52. In a telephone system, an automatic selecting switch provided with a controlling #elay which is normally in bridge of the talking; circuit of said switch, means for automatically opening up or cutting ofl said bridge, a central source of current for talkurposes, and means controlled over the ig circuit for releasing said switch, said ieasing means including a relay having both terminals thereof connected with the talking circuit.

53. In a telephone system, a line circuit, an automatic switch adapted to be controlled over said circuit, line relays for said switch, means for automatically disconnecting the line relays of said switch from the circuit after the operation thereof, a central source of current for talking purposes, and means controlled over the line circuit for releasing said switch, said releasing means including a relay provided with a winding which is connected in series in one side of the line circuit.

54:. In a telephone 'system, a plurality of stepby-step movable switches, a common battery talking circuit extending between said switches provided with means for releasing without using more than two conductors between switches, said switches having motion in one plane to select groups and motion in another plane to find a line in the selected group.

Signed by me at Chicago, Cook county, Illinois, this 16th day of January, 1907.

J flN ERICKSON. \Vitnesses:

EDWARD D. Finns, ARTHUR B. 

